1. Field of Application
The present invention relates to a process for high-efficiency catalytic conversion of carbon monoxide (CO) to carbon dioxide (CO.sub.2) of the type comprising the steps of:
feeding at predetermined speed a gaseous flow comprising carbon monoxide to a reaction space; PA1 reacting the carbon monoxide in this space to obtain a gaseous flow comprising carbon dioxide. PA1 accelerating the gaseous flow comprising carbon monoxide upstream of the reaction space. PA1 a substantially cylindrical external shell; PA1 at least one catalytic bed supported inside the above mentioned shell; PA1 an inlet nozzle in fluid communication with the above mentioned shell to feed to said at least one catalytic bed a gaseous flow comprising carbon monoxide; PA1 means for accelerating the gaseous flow supported upstream of the at least one catalytic bed. PA1 a conversion reactor comprising a substantially cylindrical shell and at least one catalytic bed supported in this shell; PA1 a duct for feeding to the reactor the gaseous flow comprising carbon monoxide; and characterized in that it further comprises: PA1 means for accelerating the gaseous flow supported in the duct. PA1 a substantially cylindrical external shell; PA1 at least one catalytic bed supported in the above mentioned shell; PA1 an inlet nozzle in fluid communication with the shell to feed to the at least one catalytic bed a gaseous flow comprising carbon monoxide; PA1 arranging upstream of said at least one catalytic bed means for accelerating the gaseous flow. PA1 a conversion reactor comprising a substantially cylindrical external shell and at least one catalytic bed supported in this shell; PA1 a duct for feeding to said reactor a gaseous flow comprising carbon monoxide; PA1 arranging in the duct means for accelerating the gaseous flow.
In the description given below and in the following claims, the term: "reaction space", is understood generally to mean a space comprising catalyst-containing means in which takes place the conversion reaction of carbon monoxide to carbon dioxide in accordance with the following formula. EQU CO+H.sub.2 O(steam)CO.sub.2 +H.sub.2
Carbon monoxide conversion reaction is very important to industry because it permits obtaining one of the basic reagents for many synthesis reactions (for example ammonia synthesis), i.e. hydrogen (H.sub.2).
The present invention also relates respectively to a reactor and an equipment for implementation of the above process, so as to a modernization method respectively for a reactor and an apparatus for catalytic carbon monoxide conversion.
As known, in the field of catalytic carbon monoxide conversion the need is ever more strongly felt to provide easily implemented conversion processes, allowing achievement of ever higher production capacities at low operating and investment costs and low energy consumption.
2. Prior Art
To meet this requirement there have been proposed in the industry carbon monoxide conversion processes in which gaseous reagents were made to flow with substantially axial, radial or axial-radial motion across a reaction space comprising at least one catalytic bed.
A process of this type is described for example in EP-A-0 372 453.
Although advantageous in some ways, the processes according to the prior art all display a serious drawback linked to the presence of water--e.g. in the form of drops--entrained in the gaseous flow comprising carbon monoxide.
Indeed, water introduced together with the carbon monoxide into the reaction space irreversibly damages the surface layer of the catalyst contained therein and makes it extremely compact or packed.
This is due in particular to the localized thermal shock caused by the immediate evaporation of the water in contact with the high temperature catalyst, and in part to the mechanical impact of the water striking the catalyst.
The primary consequence of this packing of the surface layer of the catalyst is a significant pressure drop of the gaseous flow crossing the catalytic mass and a decrease in the activity of the catalyst, with associated decrease in conversion yield (and hence of productive capacity) and high energy consumption.
This important drawback of the carbon monoxide conversion processes according to the prior art has now been known for more than two decades, and the only solution proposed until now consists of manual elimination by a worker of the packed catalyst layer and its replacement with new catalyst.
In addition, formation of the packed catalyst layer can be so frequent and penalizing for the general behaviour of the process as to require the above mentioned treatment at very short time intervals generally less than a year (3 to 9 months).
As may be readily imagined, the present solution to the above mentioned drawback cannot be considered satisfactory for industry requirements because it involves stopping the plant assigned to implementation of the conversion process, and consequently stopping of production, high maintenance and operating costs and high energy consumption.